Cannot add unique id to the new row

[Sunil Pascal]

The google form details has

Name

Age

Gender

Grade

ID

The script should create a unique ID for each row based on the grade.

Grade 1 - 5 Sub Juniors SJ00001

Grade 6 - 9 Juniors J00001

Grade 10 - 12 Seniors

If they have siblings after submitting the google form. The new row should be added with unique id based on the grade system

for example

I have written the code but its not working , can someone help me. The data is not showing the id in the second row

const UID = {
  HEADER: "UID",  // Column header for UID
  //SJ Sub Juniors/J Juniors/S Seniors/SC Seniors Completed/AC Attending College/WA Working Adult
  PREFIXES: {
    SJ: "SJ-",
    J: "J-",
    S: "S-",
    SC: "SC-",
    AC: "AC-",
    WA: "WA-"
  },
  LENGTH: 6  // Fixed length for the ID (e.g., 000001, 000002, etc.)
};

class App {
  constructor() {
    this.ss = SpreadsheetApp.getActive();
    this.sheet = this.getLinkedSheet();
    if (!this.sheet) {
      throw Error(`There is no linked form in this spreadsheet.`);
    }
    this.form = FormApp.openByUrl(this.sheet.getFormUrl());
    this.message = this.form.getConfirmationMessage();
  }
 
  // Generate UID based on the grade and a sequential number
  createUidByCategoryAndNumber(category, number) {
    let x = null;  
    x = UID.PREFIXES[category] + (10 ** UID.LENGTH + number).toString().slice(-UID.LENGTH);
    return x;
  }

  getLinkedSheet() {
    return this.ss.getSheets().find(sheet => sheet.getFormUrl());
  }

  // Determine the grade category (SJ, J, S) based on the grade
  getCategory(grade) {
    const gradeNumber = parseInt(grade.replace(/\D/g, ""), 10);
    if (gradeNumber >= 1 && gradeNumber <= 5) return "SJ";
    if (gradeNumber >= 6 && gradeNumber <= 9) return "J";
    if (gradeNumber >= 10 && gradeNumber <= 12) return "S";
    if (grade==="12th Completed") return "SC";
    if (grade==="Attending College") return "AC";
    if (grade==="Working Adult") return "WA";
    return "U"; // Default (Unknown)
  }

  // Get the last used UID from the sheet to create the next one
  getLastUsedUid(category) {
    const data = this.sheet.getDataRange().getValues();
    let lastUsedUid = null;
    // Find the last UID for the given category (SJ, J, S, SC, AC, WA, U)
    for (let i = data.length - 1; i >= 0; i--) {
      const uid = data[i][1]; // Assuming UID is in the second column (index 1)
      if (uid && uid.startsWith(UID.PREFIXES[category])) {
        lastUsedUid = uid;
        break;
      }
    }

    // Extract the numerical part and return the next number
    if (lastUsedUid) {
      const lastNumber = parseInt(lastUsedUid.replace(UID.PREFIXES[category], ""), 10);
      return lastNumber + 1;  // Increment the last number
    }

    // If no UID is found for this category, return the starting number
    return 1;
  }

  saveCurrentUid(uid, rowStart) {
    const [headers] = this.sheet.getDataRange().getDisplayValues();
    let uidHeaderIndex = headers.indexOf(UID.HEADER);
    if (uidHeaderIndex === -1) {
      uidHeaderIndex = headers.length;
      this.sheet.getRange(1, uidHeaderIndex + 1).setValue(UID.HEADER);
    }
    this.sheet.getRange(rowStart, uidHeaderIndex + 1).setValue(uid);
  }

  // Update the confirmation message with both main student and sibling details
  updateConfirmationMessage(mainStudent, sibling) {
    let message = `Registration Successful. Please Note Your ID Given Below:\n\n`;
    message += `UID: ${mainStudent.uid}\n`;    
    message += `Name: ${mainStudent.name}\n`;
    message += `Grade: ${mainStudent.grade}\n`;
    message += `Phone: ${mainStudent.phone1}\n`;
    // If there is a sibling, include sibling details in the message
    if (sibling) {
      message += `\nUID: ${sibling.uid}\n`;
      message += `Sibling Name  : ${sibling.name}\n`;
      message += `Sibling Grade : ${sibling.grade}\n`;
      message += `Sibling Phone : ${sibling.phone1}\n`;
    }

    // Set the confirmation message in the form
    this.form.setConfirmationMessage(message);
  }

  run(e) {  
 
    const values = e.values;    
    const timestamp = values[0];
    const email = values[2];
    const name = values[3];
    const phone1= values[4];
    const phone2= values[5];
    const landline= values[6];
    const grade= values[7];
    const gender= values[8];
    const transportBoolean= values[9];
    let areainKuwait = null;
    let landmark = null;
    let areainAbbasiya = null;
    if (transportBoolean === "Yes") {
       areainKuwait= values[10];
       landmark= values[11];
      if (areainKuwait === "Abbasiya") {
         areainAbbasiya= values[12];
      }
    }

//hasSibling==============================================================
    //hasSibling is not used in this registration form by default its no
    //const hasSibling = values[]; No Sibling for now
    const hasSibling = 'no';
//hasSibling==============================================================

    const category = this.getCategory(grade);
    const lastUserID = this.getLastUsedUid(category);
    const nextUid = this.createUidByCategoryAndNumber(category, lastUserID);

    const church= values[13];
    const parentname= values[14];
    const parentcontactno= values[15];
    const areainkuwaitFamily= values[16];
    const areainkuwaitOther= values[17];
// Insert the main student details into the sheet only
    if (nextUid) {      
    this.sheet.appendRow([timestamp,nextUid,email,name,phone1,phone2,landline,grade,gender,transportBoolean,areainKuwait,landmark,areainAbbasiya,church,parentname,parentcontactno,areainkuwaitFamily,areainkuwaitOther]);
    }
   // this.saveCurrentUid(nextUid, this.sheet.getLastRow());

   
//Sibling==============================================================
    let siblingNextUid = null;
    let siblingDetails = null;
    // Only append sibling entry if "YES" is selected for sibling
    if (hasSibling.toLowerCase() === "yes") {
      const siblingName = values[18]; // Sibling Name from the form
      const siblingGrade = values[19]; // Sibling Grade from the form
      const siblingCategory = this.getCategory(siblingGrade);
      siblingNextUid = this.createUidByCategoryAndNumber(siblingCategory, this.getLastUsedUid(siblingCategory));

      // Append sibling entry with the correct columns only if "YES" is selected for sibling
      this.sheet.appendRow([timestamp, siblingNextUid, siblingName, siblingGrade, phone1, "Sibling"]);
      this.saveCurrentUid(siblingNextUid, this.sheet.getLastRow());

      siblingDetails = {
        name: siblingName,
        uid: siblingNextUid,
        grade: siblingGrade,
        phone: phone1
      };
    }
//Sibling==============================================================


    // Update the confirmation message with both the main student's and sibling's details
    this.updateConfirmationMessage(
      { name, uid: nextUid, grade, phone1 },
      siblingDetails
    );

    // Optional: Log UID for debugging
    Logger.log(`UIDs generated: Main - ${nextUid}, Sibling - ${siblingNextUid}`);
  }
}

function _onFormSubmit(e) {
  new App().run(e);
}